This invention relates to a method for producing card-shaped data carriers and an apparatus for carrying out the method.
Card-shaped data carriers can be formed for example as magnetic stripe cards or chip cards which can be used as check cards, credit cards or electronic purses for carrying out financial transactions, can serve as identity cards for admittance or access control, etc. Such cards are normally made of plastic and/or paper or cardboard. Plastic cards are produced by laminating several layers or by injection molding or other suitable methods, depending on the desired properties and permissible production costs. For the following description a laminated chip card will be used by way of example, whereby the described methods can also be used for differently produced cards and also for different types of card.
Laminated chip cards consist of a plurality of layers: e.g. top protective layer, printed top cover layer, one or more intermediate layers, printed bottom cover layer, bottom protective layer. For producing such cards one produces the individual layers as foils with a certain sheet size. Then one prints the sheets for the top and bottom cover layers. Subsequently one superposes the different sheets and welds them together to a single sheet under pressure and heat. One punches the individual raw card bodies out of this sheet. Endless card production by roll lamination is likewise possible. The individual layers are thereby supplied in the form of long webs to a roll laminating machine, connected to a single web there and then divided into single cards.
Hitherto each single card has been subjected manually to a quality inspection after the abovementioned production steps; i.e. each card is compared manually with a reference card. If the card to be tested is within a given tolerance for given criteria, such as contrast of colors, no burr on the card edges, no scratches, no lint, etc., it is passed on for processing. If the card does not stand the test, which is subjective since performed by a human being, it ends as a reject. The accepted cards are then placed in the magazine of a singler which supplies the cards to a milling machine via a card transport device. With a pocket milling cycle one produces cavities for chip modules to be provided on the cards. Subsequently the chip modules are inserted into the card cavities and fixed in the cavities with an adhesive. This process is called implantation.
This method for producing the cavities has hitherto only been used in chip cards made of sheet material since with integral plastic cards (e.g. made of ABS) produced by injection molding it is easier and cheaper to produce the cavity during injection.
Problems arise from the fact that the abovementioned inspection, being manual, is subjective, time-consuming and involves error, since people are not always as focused as they should be, and thus too many rejected cards pass to final inspection. Further rejected cards arise from the fact that cards arriving at the milling machine in a wrong position are milled wrong. A further problem is that the pocket milling machine must be readjusted for some types of card with respect to the size and shape of the chip module.
The described problems can occur not only during production of the cavities but similarly in each production step in which changes are made on the cards or in production steps in which cards of a certain type are expected or in which the cards must have a defined state or assume a defined spatial position, and a deviation from the expected type/state/position cannot be excluded.
The problem of the invention is therefore to obtain a maximum quality standard and minimize rejects rates at reduced personnel expense in the production of card-shaped data carriers.
This problem is solved by the characterizing features of the invention described in patent claim 1.
According to the invention, optical testing is performed before each production step in which changes are made on the cards or which is critical with respect to the spatial position or type or state of the card.
Said testing can be used especially advantageously for production steps in which the type or state or spatial position of the cards is important. One can thus firstly ensure that the production step is not performed erroneously on cards not intended for this production step. Both can lead to rejected cards and one would lose both the costs for the preceding production steps including the step in question and the material costs incurred.
Secondly, one prevents the production step from being performed on cards which do not fulfill the minimum quality requirements defined for this production step. This avoids e.g. Further production costs being incurred for a rejected card.
The stated variations of the invention can be applied both for single cards and for sheets or webs each having a plurality of cards. The specific manner of testing in each case will be described in the following with reference to some selected embodiments.
The invention will be illustrated by a pocket milling machine used for providing card bodies with cavities for receiving chip modules. The pocket milling machine is extended by an optical detecting unit, which is disposed procedurally before the pocket milling machine according to the invention and connected with a control unit which decides whether to supply the particular card to the milling machine for milling the cavity or whether to supply the milled card to further processing. There are several embodiments of the machine described by the invention. In the following, embodiments will be described in which the optical detecting unit is disposed before the pocket milling machine.
In a first embodiment the abovementioned testing is still performed manually, but not on the individual card but on the sheet, i.e. before punching. This is much faster than checking single cards. A further advantage of checking sheets is that one detects recurrent system errors, e.g. errors produced by a faulty printing roller or scratched laminating plates. The testers check the front and back of the sheet and mark the rejected cards. They mark the cards e.g. with a fluorescent ink or a felt pen or perforate them. The applied markings need not necessarily be in the visible spectral region; one can also use for example a color detectable in the infrared region or an UV-activable substance. Subsequently the cards are punched and stacked. They are then placed in a singler from which the cards are supplied singly to the pocket milling machine via a card transport device, e.g. a conveyer belt, a robot arm with a gripping system or a rotary table. Mounted before or on the pocket milling machine according to the invention is an optical detecting unit which recognizes whether a card is marked. If a fluorescent or UV-active marking is used the card is exposed to UV light. If no marking is present no fluorescent light is reflected. If the card has a fluorescent marking fluorescent light is reflected. This is registered by a detector. One proceeds similarly with markings detectable in the infrared region. If felt pen is used the optical detecting unit is a camera. One can reconstruct the original card position within a sheet, as is necessary for detecting system errors, with reference to the order of the single cards. It is likewise possible to provide the cards with a marking indicating their original position within the sheet. This marking can be for example printed, or molded during laminating by suitable design of the laminating plates. The marking is thereby either designed or disposed, e.g. in the area of the cavity, so as not to disturb the appearance of the card.
A control unit (in the simplest case a relay) connected with the optical detecting unit and with the card transport device and the milling machine decides after the optical testing on the further process of manufacture of the card:
no marking: the normal program is run through, i.e. cards stacked in magazines are inserted into singler, transport to pocket milling machine, milling cavities, further transport to stacking apparatus, stacking,
a marking: the normal program is interrupted or altered, i.e. marked cards are supplied to a stacking apparatus for rejected cards before or after the milling machine (in the latter case the milling machine remains turned off).
In this first embodiment, cards arriving in a wrong position (laterally inverted or front and back switched) are not recognized and thus become rejected cards since they are milled at the wrong place. Therefore, no robot arm is used in this first embodiment since it would be too expensive for this embodiment and its spectrum of abilities would not be exploited at all.
Supply to the stacking apparatus is done with a switch in the version with card transport effected by a conveyer belt. In the version with card transport effected by a rotary table it is done e.g. by the rotary table stopping above the rejected card stacking magazine and the corresponding card (which is in a card receiving pocket whose bottom is formed by a further table having a gap at a certain place) falling into the stacking magazine by rotation of the bottom table relative to the rotary table until the gap arrives under the receiving pocket.
In another version the bottom table, which again has a gap, stands still. A card only falls through into the rejects shaft when the rotary table stops at the same position where the bottom table has its gap.
Further possibilities with the use of a rotary table are to blow the cards away from below and supply them to the magazine via a ramp or to suck them pneumatically by a suitable apparatus and then supply them to the rejects magazine. There are surely even more possible embodiments here.
In a second embodiment, manual inspection is fully eliminated. The optical detecting unit no longer consists of a simple detector but of a digital camera connected with a computer. As in the first embodiment of the control unit, the computer must drive the card transport device, the milling machine and the switch. Card production itself remains the same: producing sheets by laminating individual layers, punching out individual cards, manually filling cards into the singler magazine, transport with a card transport device to the pocket milling machine, milling out the cavity for the chip module, transport to a stacking apparatus, manually transport to the implanter, implanting the chip module. The camera, which is installed before the milling machine, in terms of the direction of production, takes a picture of a card. This is done either while a pocket is being milled into the previously conveyed card, i.e. in a standstill phase, or during conveyance, which does not lead to blurred pictures with the speed of exposure of present-day cameras. The computer connected with the camera has stored a reference picture of a sample card. The computer now decides independently on the further process of manufacture of the card. If the card has no scratch, and sharpness, contrast and colors of the layout are within a given tolerance, the card is passed on to milling. If this is not the case, or the card arrives at the camera in the wrong position, e.g. on the back or laterally inverted, the card is directed past the milling process (e.g. via a switch located before or after the milling machine when a conveyer belt is used) and supplied to a stacking apparatus for rejected cards, or it is reversed by an adequate apparatus and supplied to the milling machine in the right position. If the switch follows, the milling machinexe2x80x94driven by. the computerxe2x80x94lets the card pass. Hitherto, rejected cards had to be separated from accepted cards manually after milling. Cards which arrived at the milling machine in the wrong position became rejects through the milling. It is also possible, however, to supply rejected cards and the cards arriving in the wrong position to separate stacking apparatuses by a swiveling, computer-driven switch. This can also be done by connecting two switches in series. Or one uses a switch which can swivel to three outputs (milling machine, rejected card stacking apparatus, cards arriving in the wrong position to be reinserted). Said cards to be reinserted can also be supplied immediately to the milling machine by a suitable card-reversing apparatus. The accepted cards are either stacked and manually brought to the implanter or conveyed to the implanter directly without stacking. There are again different possibilities using a rotary table as a card transport device:
the rotary table stops above the corresponding shaft (rejected cards, cards to be reinserted or reversed) and suitable relative rotation of the bottom table leads to stacking (see above),
the cards to be reversed fall onto a reversing apparatus and are resupplied to the rotary table in the right position, or the reversing apparatus is located directly in the rotary table.
The use of a robot arm as a card conveying device is the most expensive but most easily realized solution. The robot arm fetches a card from the provided magazine, places it under the camera, a picture is taken and compared with a reference picture in the computer, the card is reversed, a picture of the back taken and again compared with the corresponding reference picture. Then, the computer causes the arm to take the further steps: conveying on to the milling machine or the stacking device for rejected cards, or turning the card into the right position and conveying it on to the milling machine.
This possibilityxe2x80x94photographing the cards from both sidesxe2x80x94is the most advantageous embodiment of the invention, since the error rate is lowest and the throughput times are shortest. It can be realized not only with the use of a robot arm but also with the use of a rotary table or band as a card transport device.
Double-sided photography of the card can be effected in three ways:
using two tandem-mounted cameras and two reversing apparatuses (photo-graphing one side of card, transport, reversal, transport, photographing second side of card, transport, possibly repeated reversal with respect to front and back and to lateral transposition, transport to milling machine);
using a camera and a reversing apparatus;
using one camera disposed above and one disposed below the passing cards and a reversing apparatus (which is not used for photography but for turning cards into the right position).
The computer controls the complete procedure: removal of individual card from singler, transport to camera, photography of one side, comparison with reference pictures (front, back), reversal of card, comparison with reference pictures, decision (rejected card, right position), turning card into right position and transport on to milling machine or transport directly to rejects magazine (this being the second version).
Since there are different types of card differing in size, shape and depth profile, it is an advantageous development of the invention if the optical detecting unit recognizes the type of card and requests the corresponding milling program or rejects the card if its type does not correspond to the expected type.
For position detection it is not absolutely necessary to evaluate the total card surface. One can also confine oneself to a section of the card surface. In order to determine the position of the card one defines a section of the printed image of the card surface as a reference. This reference is so defined that the position of the card is clearly derivable therefrom. Thus, a new reference is to be defined for each new layout of the printed image. As an alternative to this procedure one can define a suitable symbol and print it on the card in the area of the later cavity. This symbol could always be the same regardless of the layout of the card surface so that no adaptation is necessary upon a change of layout.
Optical evaluation of the printed image or sections of the printed image can be used not only for position detection but also when a production process handles different types of card and/or different types of module and it is to be ensured that the right type of card and right type of module are brought together. If several types of module are available, they can be distinguished for example by the contact layout or by a manufacturer""s identification applied to the module.
The described optical test procedures are not only suitable in connection with production steps performed on single cards. They can also be used in production steps performed on sheets or webs. If the optical testing of a sheet shows that a plurality of cards do not meet the quality requirements, one can consider eliminating the total sheet instead of marking the particular cards and then eliminating said cards. One will normally choose this variant when so many cards are affected that it is more cost-effective to eliminate the total sheet.
In order to test the quality of milling one can dispose an optical testing station after the milling machine, in terms of the direction of card transport. This testing station can test the cavity produced by the milling machine with respect to position, depth and shape. If the test shows insufficient quality of milling, the card can be eliminated as a reject. Moreover, the test result can be used for readjusting the milling machine or causing a readjustment. One can also derive from the test result whether the edge of the milled cavity has a burr, whether the cavity is soiled for example by chips and whether the milling machine is defective and one can expect the same error to be produced continuously if there is no intervention.
Optical testing stations can be used not only in the production of laminated cards but for example also in production by injection molding. The testing station is disposed after the injection molding machine and tests the cards outputted by the injection molding machine. This is recommendable in particular if the cards outputted by the injection molding machine already have a printed image and/or a module.